Add test case for Animation and UnitCurve

[Kyle-Ye]

• Added AnimationTests
• Added UnitCurveTests and fixed a bug in UnitCurve
• Added UnitCurveCompatibilityTests

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 19.34%. Comparing base (77e642b) to head (e99245e).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...penSwiftUICore/Animation/Animation/Animation.swift	0.00%	1 Missing ⚠️
...penSwiftUICore/Animation/Animation/UnitCurve.swift	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #389      +/-   ##
==========================================
+ Coverage   18.95%   19.34%   +0.38%     
==========================================
  Files         432      432              
  Lines       23329    23329              
==========================================
+ Hits         4422     4512      +90     
+ Misses      18907    18817      -90     

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